1. Field of the Invention
The present invention relates to a dielectric filter. More specifically, the present invention relates to an integral type dielectric filter, in which a plurality of resonance elements are formed within a dielectric block.
2. Description of the Prior Art
A conventional dielectric filter of this type is disclosed, for example, in the International Publication No. WO 83/0285 published internationally on Aug. 18, 1983. In the dielectric filter, each resonance element R may be coupled by the gap capacity C formed by the electrodes on the open end side of each resonance element R as shown in an equivalent circuit diagram of FIG. 1.
In the prior art cited, the dielectric block can be easily produced, since holes or slits for coupling each resonance element are not needed to be formed in the dielectric block. However, in the prior art, it is necessary to form electrodes on the open end surface for forming the gap capacity to couple each resonance element. In order to form the electrodes on the open end surface, additional processings such as etching or patterning different from the forming process of an outer conductor or inner conductors are required, thus resulting in complicated processings.